Skyjack SJ1044 TH - Hydraulic System; All Controls Inoperative; No Boom Functions

121
SJ1044 TH, SJ1044 THS, SJ1056 TH, SJ1056 THS, SJ1256 THS
230790ABA
Hydraulic System Section 4 – Troubleshooting Information
4.3 Hydraulic System
4.3-1 All Controls inoperative
1. Worn or defective pump shaft or coupling.
Check pump shaft and coupling. Replace if
defective
2. No PTO rotation Repair transmission, or flex plate.
3. Hydraulic oil level low Check oil level. Fill to proper level.
4. System pump P1 is out of adjustment or is
defective.
Refer to section 5 for pump set up/test procedure.
Repair or replace if defective
5. RV1 misadjusted or defective Adjust pressure, replace if defective
4.3-2 No Boom Functions
With following conditions:
▪
All Boom Functions Inoperative.
1. EC1 defective Replace if defective
2. Orifice OR2 plugged Remove and inspect, clean or replace as required.
3. PR1 pressure reducing valve misadjusted or
defective
Adjust pressure, replace if defective
With following conditions:
▪
No Boom Raise
1. Stuck or defective joystick JS1
Clean valve. Check operation of valve. Repair or
replace valve as required.
2. Boom up enable valve 2H-19A stuck or defective.
Clean valve. Check operation of valve. Repair or
replace valve as required.
3. Stuck or defective lift valve V1.
Clean valve. Check operation of valve. Repair or
replace valve as required.
4. LS check valve CV9 blocked or defective
Clean valve. Check operation of valve. Repair or
replace valve as required
5. Stuck or defective lift counterbalance valves CB1,
CB1-1.
Clean valve. Check O-rings on valve. Repair or
replace valve as required.
6. Stuck or defective lift counterbalance valves CB2,
CB2-1.
Clean valves. Check O-rings on valve. Repair or
replace valve as required.
7. Defective lift cylinder C3 and/or C4.
Check seals on cylinder. Replace as necessary.
Replace cylinder if defective